Single stage cold start and evaporative control system using a bimodal adsorbent bed

ABSTRACT

As cold start is initiated in a spark-ignition internal combustion engine, lower molecular weight constituents of a fullrange gasoline are selectively eluted by an elution system including an adsorbent bed of adsorbent material (cold start cycle). Under such circumstances, the adsorbent bed forms an elution zone within a cannister assembly. Furthermore, when the engine is in an inoperative state (vapor capture cycle) the same adsorbent bed is also capable of performing a second function: it adsorbes evaporative emissions originating from within the gasoline tank and carburetor bowl.

' United States Patent Csicsery 5] Dec. 16, 1975 [5 1 SINGLE STAGE COLDSTART AND 3,221,724 12/1965 Wentworth 123/136 EVAPORATIVE CONTROL SYSTEMUSING 3,635,200 1/1972 Rundell et a1. 123/3 3,831,572 8/1974 Csicsery123/3 x A BIMODAL ADSORBENT BED 3,838,673 10/1974 Csicsery et al 123/3 Xlnventor: Sigmund M. Csicsery, Lafayette,

Related US. Application Data Continuation-in-part of Ser. No. 295,028,Oct. 4, 1972, Pat. No. 3,831,572.

Assignee:

US. (:1 123/180 R; 123 3; 123/1875 R; 123/127 1m. (:1. F02M 1116 Fieldof Search...123/179 (3,3,180 R, 187.5 R, 123/11913, 127

Primary Examiner-Wendell E. Burns Assistant Examiner-David D. ReynoldsAttorney, Agent, or Firm-R. L. Freeland, Jr.; H. D. Messner [5 7]ABSTRACT As cold start is initiated in a spark-ignition internalcombustion engine, lower molecular weight constituents of a full-rangegasoline are selectively eluted by an elution system including anadsorbent bed of adsorbent material (cold start cycle). Under suchcircum stances, the adsorbent bed forms an elution zone within acannister assembly. Furthermore, when the engine is in an inoperativestate (vapor capture cycle) the same adsorbent bed is also capable ofperforming a second function: it adsorbes evaporative emissionsoriginating from within the gasoline tank and carburetor bowl.

8 Claims, 8 Drawing Figures U.S@ Patsm Dec 16,1975 Sheet10f3 3,926,168

Illllll US Patent Dec. 16, 1975 Sheet2 of3 3,926,168

US. Patent Dec. 16,1975 Sheet30f3 3,926,168

SINGLE STAGE COLD START AND EVAPORATIVE CONTROL SYSTEM USING A BIMODALADSORBENT BED RELATED APPLICATIONS I The subject application is acontinuation-in-part of fSer. No. 295,028 for SingleStage Cold Start andEvaporative Control Method and Apparatus for Carrying Out Same filedOct. 4'. 1972, now US. Pat.

No. 3,831,572, issued Aug. 27, 1974.

Other applications assigned to the assignee of the subject applicationcontaining common subject matter incorporated herein by reference,include:

Title .bent bed, but within a second adsorbent bed located coextensivelywith, but coaxially exterior thereof. However, since the cannisterassembly supporting both first and second beds had to include aninternal separation wall, experience has shown that the resultingcannister assembly could be rather costly and time-consuming tofabricate.

Serial No.

Two-Stage Cold Start and Evaporative Control System and Apparatus forCarrying Out Same Cold Start Method and Apparatus for Carrying Out SameFuel Injection Cold Start Evaporative Control Method and Apparatus forCarrying Out Same Two-Stage Fuel Injection Cold Start Method andApparatus for Carrying Out Same Fuel Injection Cold Start andEvaporative Control Method Using a Bimodal Adsorbent Bed Sigmund M.Csicsery and Bernard F. Mulaskey John F. Senger Sigmund M. C sicserySigmund M. Csicsery and Bernard Fv Mulaskey Sigmund M. Csicsery Filed10-4-72 now US. Pat. No. 3,838,673 295,041

Filed 10-4-72 now abandoned 295,040

Filed 10-4-72 now US. Pat. No. 3,838,667 295,030

Filed 10-4-72 now US. Pat. No. 3,826,237 448,775

Filed 3-6-74 BACKGROUND OF THE INVENTION The present invention relatesto cold starting and evaporative emission control of a spark-ignitioninternal combustion engine and has for an object the provision of asimple and effective cold start and evaporative control system for usein such engine i. for selectively eluting from a full range fuel flowingto the engine, only the lower molecular weight constituents at coldstart so to allow quick starting of the engine without excessive amountsof unburned hydrocarbons appearing at the exhaust (cold start cycle) aswell ii. for adsorbing evaporative emissions from the gasoline tank andcarburetor bowl when the engine is not operating (vapor capture cycle),without mileage loss.

Higher molecular weight constituents adsorbed during the cold startcycle and/or light, evaporative emissions adsorbed during the vaporcapture cycle of the engine are subsequently purged from the engine, byconsumption interior thereof, but only after the engine has warmed andfull range fuel is being utilized.

In my parent application cited above, I taught how cold starting of aspark-ignition, internal combustion engine could be enhanced, suchenhancement occurring without generating unburned hydrocarbons at theengines exhaust. Specifically, as cold start conditions occur (coldstart operating mode), just enough lower molecular weight constituentsof a full-range fuel can be dynamically eluted for cold starting of theengine. The described elution system includes an adsorbent bed ofadsorbent material packed within a cannister assembly. Fuel flow controlfrom a fuel reservoir is by means of a controller circuit acting througha valve and conduit network. Initiation of the cold start cycle is Inaccordance with the present invention, rather than requiring complex,double-wall construction, my cannister assembly now requires only asingle adsorbent bed for performing the aforementioned dual functions.Thus in one embodiment, the cannister assembly uses only a singleunitary sidewall to form the annular support space at its interior. Intothe unitary space adsorbent materials are packed capable ofinterchangeably functioning as either an elution or emission captureadsorbent bed. Inasmuch as the two separate functions areinterchangeable, it is essential that the adsorbent material(constituting the aforementioned adsorbent bed) be properly classifiedfor these functions, viz, either polar or nonpolar or a combinationthereof.

In many applications, a composite mixture of polar and nonpolaradsorbent materials is preferred. The range of the mix ratio, by volume,can be varied depending upon the nature of conditions encountered in thefield. That is, in geographically humid zones of the world, such asfound in the southern part of the United States, there may be arequirement for the use of greater amounts, by volume, of the nonpolaradsorbent contituent material for the purpose of increasing capture areaof the cannister assembly. Results: increased probability of totaladsorption of vapor emissions generated within the fuel system.Similarly, in colder climatic zones where start conditions are moresevere, there may be some advantage to provide greater amounts of polaradsorbent material during the cold start cycle of the engine. The keyrequirement in both cases, of course, remans to provide polar andnonpolar adsorbent contituent materials in a combination that assuresboth efficient elution and capture modes of operation within thecannister assembly of the present invention.

Construction of the improved cannister assembly in accordance withpresent invention can vary. For example, in one embodiment a simplecylinder can be plugged at both ends with solid, annular pole pieces.Entry and egress of the engine fuel is by means of radially extendingfitting conduits connected through the valve and conduit network to thefuel reservoir.

All operating cycles are automatically controlled through a controllercircuit similar to one I previously proposed and described in theabove-identified parent application. The control circuit, in turn, actsin conjunction with the valve and conduit network to allow (or prevent)fluid flow depending on the operating cycle.

In more detail, during the cold start cycle, the valve and conduitnetwork is arranged to allow free passage of the full-range fuel intocontact with the adsorbent bed say through a radial inlet fitting andthence by percolation thereover. Selective retardation of the highermolecular weight compounds, vis-a-vis the lower components then occurs.Thereafter, the latter constituents pass from a second radial outletfitting conduit to the fuel well of the carburetor, and thence are mixedwith air in a preselected air-fuel ratio. Results: the engine startseven under the most severe climatic conditions. Since the starting cycleis usually quite short, say from I to 15 seonds, the residence time forthe high molecular weight compounds within the elution zone ispreferably l to 2 orders longer say from 1 to 3 minutes. Thus, theheavier compounds remain selectively adsorbed with the adsorbent bedduring starting of the engine. Thereafter, the adsorbent bed isdisconnected from direct fuel flow by the controller. The full-rangefuel from the reservoir, then is forced to flow in a direct path to thecarburetor. As the full-range fuel is used and the cannister isdisabled, it should be noted that the latter undergoes depressurization.Result: as the engine .warms and hot air is passed adjacent to thecannister, adsorbed materials (adsorbates) within the adsorbent bed, areeasily purged from the system. The resulting purged emissions flow fromthe bed through the valve and conduit network and thence to the intakeof the carburetor for consumption within the engine.

In still more detail, during the inoperative state of the engine, (thevapor capture cycle), the same adsorbent bed interior of the cannisterassembly is automatically placed in fluid contact with the carburetorfuel well and the gasoline tank through operation of the same controllerand network system. Thus, the evaporative emissions are free to passinto, and be captured by the aforementioned adsorbent bed. Since studiesindicate that up to 15 percent by volume of the total vapors admittedinto the atmosphere during inoperativeness of LC. engines are traceableto evaporative emissions originating from fuel sources of such engines,the present invention provides a useful solution to a seriousenvironmental problem.

Since the function of the associated valve and conduit network and thecontroller circuit is to place the adsorbent bed of the cannisterassembly in fluid flow relationship with relevant elements of the fuelsystem as required, it is apparent that after the engine has beenstarted and adequately warmed, adsorbates within the adsorbent bed (dueto the elution and capture cycles) can be automatically purged from thecannister: gases (either' full or partial engine air or manifold exhaustgases) can be passed adjacent to the cannister assembly, as required.

Although the prior art has suggested both polar and nonpolar adsorbentmaterials for use in enhancing operation of LC. fuel systems, there hasbeen no suggestion of using commonly housed adsorbent materials in anunitary elution system to serve two functions: (i) selectively elutingfrom a full-range gasoline, only light, low molecular weight componentsthereof, to assure a smooth pollution-free start of a spark-ignitioninternal combustion engine while alternatively (ii) providing forcapture of evaporative emission originating from the associated fuelsystem when the engine is in an inoperative state.

Further objects, features and attributes of the present invention willbecome apparent from a detailed description of several embodimentsthereof, to be taken in conjunction with the following drawings inwhich:

DESCRIPTION OF THE FIGURES FIG. 1 is a schematic view of a portion of anengine fuel system incorporating the present invention illustrating atypical carburetor and air cleaner assembly interconnected between acold start evaporative emission system of the present invention, saidcold start evaporative control emission system including a cannisterassembly housed within the air intake line of the air cleaner assemblyunder regulation of a valve and conduit network controlled by acontroller circuit;

FIG. 2 is a partial cutaway of the cannister assembly of FIG. 1;

FIG. 3 is an end view taken along line 33 of the cannister assembly ofFIG. 2;

FIG. 4 is another embodiment of the present invention illustrating inside elevation a dual flow cannister assembly mounted, as by a platformto the firewall of the engine compartment;

FIG. 5 is a top elevational view, partially cutaway, of the modifiedcannister assembly of FIG. 4;

FIGS. 6 and 8 are fragmentary views of the valve and conduit network ofFIG. 1 illustrating the position of the valve network in two positions:(i) after cold start has been achieved and the engine is at runningtemperature so that the cannister assembly can be desorbed by passinggases in heat transfer contact therewith; and (ii) after the engine hasbeen placed in an inoperative state so that the cannister assembly isconnected to the vapor zones of the fuel system (vapor capture cycle),respectively; and

FIG. 7 is a partially schematic view illustrating an alternateembodiment by which air can be heated to an elevated temperature tobetter desorb the cannister assembly of FIG. 1;

DESCRIPTION OF A SPECIFIC EMBODIMENT Referring now to FIG. 1, there isillustrated an engine fuel system 10 connected to an engine intakemanifold 11 of a spark-ignition internal combustion engine (not shown).Fuel system 10 of the present invention includes an air intake system12, a carburetor 13, a fuel intake system 14, that includes coldstart-evaporative control system 15 of the present invention.

To form a combustible air-fuel mixture, air enters by way of air intakesystem 12, say by way of air inlet line 16a, and is filtered at an airfilter interior of an air filter housing 160, before entry intocarburetor l3.

Carburetor 13 includes choke and throttle valves 17 and 18,respectively, a fuel well 19, and a discharge nozzle 20. Fuel well 19contains a metered quantity of gasoline to be mixed with air passingdischarge nozzle 20. The resulting fuel-air mixture passes throughintake manifold 11 into the engine combustion chambers (not shown) wherecombustion occurs. Supplying fuel well 19 with a metered quantity ofgasoline is by means of the previously mentioned fuel intake system 14.

The fuel intake system 14 includes a gas tank 23 containing a reservoirof full-range fuel (i.e., a 'fullboiling gasoline), a fuel pump 24 andthe cold startevaporative control system 15 of the present invention.Briefly, the cold start-evaporative control system 15 includes a valveand conduit network'25 in fluid contact with the discharge side of fuelpump 24 but under operative control of controller circuit 26 to provideselective flow relative to cannister assembly 27. As shown in FIG. 1,the cannister assembly 27 is mounted adjacent to the air intake system12, say within air inlet line 16a. Fuel flow relative to the cannisterassembly 27 is selectively controlled, as explained below, by the valveand conduit network 25 through controller circuit 26.

The valve and conduit network 25 is seen in FIG. 1 to include cold startinlet and exist valves 25a and 25b, respectively, controlled as follows:(i) mechanically by relay means 26a of the controller circuit 26 throughtransducer 26d and (ii) electrically through bimetal temperature switch26b, ignition swtich 26c and battery 26f. A second relay 26e ofcontroller circuit 26 is seen to control operation of evaporativeemissions control valve 250 through mechanical transducer 26g. Duringthe cold start cycle, the control valve 25c is placed in an inoperativecondition as shown in FIG. 1; but, during the vapor capture cycle, it isactivated to assume the position depicted in FIG. 8. During suchoperations, the transducers 26d and 26g are made to convert rectilineartravel of the relay means 26a and 262 to rotational motion of thecontrol valves as explained below.

Cold-Start Evaporative Control System 15 With reference to FIG. 1,during cold start of a sparkignition, I.C. engine, a full-range fuel,i.e., a full-boiling gasoline, having high and low molecular weightconstituents, is conveyed from gas tank 23 through fuel pump 24 into thevalve and conduit network 25 to cannister assembly 27 and thence fromthe cannister assembly 27 to fuel well 19 of the carburetor 13. Since akey in providing efficient cold starting conditions lies in theselective elution of light, lower molecular weight components, a briefdiscussion cannister assembly 27 seems to be in order and is presentedbelow.

Cannister Assembly 27 Construction of the cannister assembly 27 canvary. In FIG. 2, the cannister assembly 27 is mounted within the intakeair line 16a of the air intake system 12. It is preferably cylindrical.Its overall diameter must be kept to a minimum so as to allow sufficientair to bypass into the carburetor. Within its interior, a bed ofadsorbment material indicated at 28 is provided. To accommodate therequired volume of the afore-constituted adsorbment material, the lengthof cylindrical housing 30 may have to be about as long as the housing ofair line 16a. Support of the housing 30 can be brought about by weldinganchors 31 to side Wall 32 of the housing 30 as well as to the air line16a. The sachets -31 are previdea with bares through which @616 startinlet anaemia fie ting" eeaduits 33 and 34 as well as evaperativefitting eei auit as are attached. Endpeie pieces 36 and 37 are welded attheir edges re the side wall 32 of the heusing 30. Each pole piece 36,37 is a'solid annulus having no openings therethrough. Accordingly,intake air exterior of the housing 30 is not allowed to directly mixwith fuel continuously flowing through the fitting conduits 33 and 34 ofthe cannister assembly 27.

During operations related to the cold starting of the engine, controlledseparation of the fuel components within the cannister assembly 27occurs in a straightforward fashion. That is, as shown in FIG. 1,full-range fuel is seen to flow from the gas tank 23 and fuel pump 24through conduit 40 to the inlet cold start valve 25a and thence throughinlet fitting conduit 33 to the interior of cannister assembly 27.Within the assembly 27 controlled separation of the fuel componentsoccurs. Result: light molecular weight liquid constituents forming acold start effluent appear at outlet fitting conduit 34. The effluentthen is quickly conveyed through outlet valve 25b and conduit 41 to thecarburetor 13. At the carburetor 13, the light, lower molecular weighteffluent mixed with air to form a efficient cold start airfuel mixturefor the engine.

Since separation of the heavy molecular weight vis-avis light groupswith the cannister assembly 27 is based on the functionalcharacteristics of the adsorbent material within the cannister assembly27, a brief discussion of adsorption systems in general seems to be inorder and is presented below. However, recall that such adsorbentmaterials also function as a vapor emission capture zone when the engineis placed in an inoperative state. For example, when evaporative controlvalve 25c is in an active condition, as depicted in FIG. 8, the vaporzones of thefuel well 19 and gas tank 23 are seen in FIG. I to connectto the interior of the cannister assembly 27 as follows: (i) for fuelwell 29 via conduit 42, evaporative control valve 25c and conduit 35,and (ii) for gas tank 23 via conduit 43, control valve 250 and theconduit 35. Thus, the didactic discussion which follows has been dividedalong similar lines.

During the cold start cycle, the side wall 32 of the cylindrical shellhousing 30 of FIG. 1, forms essentially a column of a solutionadsorption, frontal analysis chromatography as classified in accordancewith Kirk- Othmer Encyclopedia of Chemical Technology, 2nd Ed., Volume5, page 418. In accordance with Kirk-Othmer op. cit., suchclassification is essentially based on the nature of the mobile phase ofthe system percolating through an adsorbent material generally indicatedat 29 in FIG. 2.

Initially full-boiling gasoline enters by way of inlet fitting conduit33. Thereafter, it percolates through and about the adsorbent bed 28. Atthe outlet fitting conduit 34, the order of elution is a function of theorder of polarity of the constituents of the full range constituentssince the individual molecules of the heavier components move at aslower rate (between the mobile and secondary phases) than do thelighter constituents.

Intermediate evaporative fitting conduit 35 is not free to passconstituents from the adsorbent bed 28 during the cold start cycle. Asseen in FIG. 1, the evaporative control valve 25c is in an inoperativestate, and thus prevents flow of the gasoline constituents therethrough,as previously mentioned. Within the interior of the adsorbent bed 28,the causes for separation of the constituents can be for a multiplicityof reasons, inter alia, the polarity (or nohpolan'ty) characteristics ofthe constituents seem ta be a relevant criterion for separation classiflatiofis In that different relative velocities are thought te beimparted to the individual 7 molecules of thegroupingsso'that theleaststrongly adsorbed low molecular weight components :elute as a groupat the outlet fitting conduit 34 first, followed by a second groupingcontaining say both the light and heavy molecular weight constituentsand so forth until all constituents have appeared.

Residence time of the lighter components within the adsorbent bed 28 isalso a function of rather conventional engineering factors including thelength of the cylindrical housing 30 as well as the pressure drop of theformer during percolation of the fluids through, the adsorbent material29. The flow rate of the mobile phase must be slow enough to allowmaximum transfer of the molecules of the heavier constituents into andfrom the stationary and mobile phases yet fast enough to provide ampleamounts of lighter components for quick starting of the engine.Howe'tfer, 'care ought be exercised in regard to the residence time ofthe heavier components. Since selective retardation of the heavierconstituents due to relative polar-nonpolar interaction between theheavier components and adsorptive material 29, can be quite long, say;l3 minutes, while the typical starting cycle of a modern engine can bequite short, say from 1 second up to seconds (except when problems ofstarting occurs), the heavier constituents usually remain adsorbedduring starting. The aforementioned conclusion assumes, of course, thatthe composite adsorbent material 29 constituting the ad sorbent bed 28is of a compatible classification to perform both elution and vaporcapture functions as discussed below.

Classification of Adsorbent Material 29 As previously mentioned, duringelution of lowmolecular weight liquid fuel contituents, competition forthe heavier molecular weight groupings of the fullrange fuel is believedto be, more or less, dependent on .its selective polar interaction withthe adsorptive material 29 constituting the adsorbent bed 28. The degreeof interaction, in most, but not all cases, is believed to be directlyrelated to the magnitude of the polarity of the material. A general ruleseems to be: the greater the polarity, the greater the interaction.Thus, in accordance with the present invention, the adsorptive material29 should have (preferably in addition to a nonpolar constituent, forreasons explained below) a polar element, say one selected from thefollowing non-exclusive listing of popular polar adsorptive materialsfor proper operation as a cold start fuel effiuent generator:

Polar Adsorptive Materials Remarks Activated Preferred Ion-exchange onlyi Commonly used in liquid-liquid partition chromatography However,during operations as an adsorber of evaporative emissions, as when the,evaporativecontrol valve 250 assumes theposition,depictedin-EIG. 8, thepreferred polar classification of the material 29 is reversed. Thisassumption implies that the system requirements are such that the bed-28mustemploy materials which possess the most effective. capture surfaceper unitvolume of material. Accordingly, the adsorptive material 29should also contain, say as a second element thereof, a nonpolarcomponent, say one selected from the following non-exclusive listing ofnonpolar adsorbent materials in order to most effectively carry out thevapor capture aspect-of the present invention.

Nonpolar Adsorbent Material Remarks Organic only Metallic "only Informing the composite bed 28, the ratio, by volume,.of polar to nonpolarmaterial is preferably about 1:1. In some cases, however, the ratio canbe varied to accommodate changed conditions, e. g., where the system ofthe present invention is used in the more humid climates of the world,there may be a need to use greater amounts of the nonpolar constituentto provide a larger emission :capture area within the bed 28. Also, inother areas of the world as whre cold start conditions are more severe,it may be advantageous to use greater amounts, by volume, of the polarmaterial as the chief adsorbent component. However, since there can be alarge overlap of both functions within certain known adsorbent materialsthe adsorbent material 29 constituting adsorbent bed 28 need not be adual component mixture but can utilize a single component system,provided it can perform in both the cold start and vapor capturefunctions, as outlined above.

Of course, the adsorbent material 29 can be formulated in a variety ofways for use within the cannister assembly 27. For example, theadsorbent material 29 can be arranged in granular, pelletized orpowdered form. Preparation is straight-forward: the adsorbent materialshould be calcined, acid and base washed, neutralized, and size gradedprior to insertion within the housing 30, say along lines set forth inKirk-Othmer, op. cit;, Volume 1, page 460. Since as previouslymentioned, during elution the flow rate of the full range gasolinewithin the bed must be slow enough to allow maximum transfer of themolecules of the heavier compounds into and from the stationary andmobile phases, the size of the polar component of the adsorbent material29, if used, should be such as to minimizethe pressure drop across acannister assembly 27 without adversely affecting its ability to adsorbthe heavier .con-

.stituents. In this regard, an adsorbent bed 28 having about a 11-liter-capacity can be filled with activated alumina (8. by 14mesh).;and such a bed has been found to ..adsorb from 200 300,ml ofheavier constituents while MODIFICATION In FIG. 4, the support of thecannister assembly 27 differs markedly from that shown in FIG. 1. Thecannister assembly 27 of FIG. 4 is seen to be mounted by shell housing50 to a platform 51 which in turn is attached to a firewall (not shown)of the engine compartment. Additional space afforded by the platform 51allows for a more complex constructural design of the cannister assembly27.

As shown, a series of upright tubular means 52 is constructed to carrythe gasoline entering inlet chamber 53 along a series of sinusoidalpasses through the interior of the cannister assembly 27 to exhaustchamber 55, such passageways resembling those provided in a conventionaltube-and-shell heat exchanger. The series of sinusoidal passes made bythe gasoline are indicated by solid arrows 54 while the dotted arrows 54(see FIG. indicate the direction of the air phase flow. In the depictedarrangement, tube-side gasoline is conveyedduring cold starting-throughthe tubular members 52 between the inlet and exhaust chambers 53 and 55respectively (multipass percolation) through adsorbent material 56packed within the tubular members 52 as well as within the chamber 53and 55. Due to increased total length of the tubular members 52, theresulting adsorbent bed is likewise greatly enlarged over that depictedin FIGS. 1 and 2. The absolute length of the cannister assembly 27 ofFIG. 4 can be correspondingly reduced, if desired, or if kept atcomparable absolute lengths greatly improves elution efficiency. Thus,not only does the effluent at the exhaust chamber 55 consist essentiallyof low molecular weight liquid constituents during the cold start cycle,as previously explained, but also the heavier constituents re mainadsorbed within the adsorbent material 56 until long after the enginehas warmed up. That is to say, be cause the heavier constituents areretarded during percolation through the adsorbent material 56 for alonger time than required to usually start the engine, the effluentwithin the carburetor per each starting cycle of the internal combustionengine is limited essentially to the lightweight, low molecular weightconstituents.

Further constructural differences between the embodiments depicted inFIG. 1 and FIG. 4 are readily apparent. For example, in FIG. 5, theshell housing 50 is seen to be rectangular in cross-section whereby theassembly forms a parallelepipedon. Also, the shell housing 50 is alsoseen to include end walls 58 and 59. Each end wall 58 and 59 includes aseries of ports 60 to allow selective entry of hot, exhaust gasesadjacent to but generally exterior of tubular member means 52 withininterior of shell housing 50. End wall 58 is also seen to attach by wayof fasteners to the air cleaner housing 16c. End wall 59 is seen to beconnected to a conduit 61 having a remote end (not shown) connected to asource of exhaust gases, say the exhaust manifold of the engine.

Of course tubular members 52 need not be discontin uous so as requirethe use of intermediate chamber 57 (FIG. 4) to reverse the flow of themobile phase; e.g., the tubular members 52 can be U-shaped with remoteends in fluid contact with inlet and exhaust chambers 53, 55,respectively.

Although the embodiment depicted in FIG. 1 utilizes intake air to theengine for purging of the cannister assembly, it should also be notedthat it could also con template utilization of gases from the exhaustmanifold for this purpose. In this regard, assume that the engine hasbeen started and warmed using the full-range fuel, i.e., the inlet andoutlet cold start valves 25a and 25b have been placed in the positionsdepicted in FIG. 6 so that the full-range fuel is free to directly enterthe engine. carburetor. That is, full-range fuel bypasses the cannisterassembly via flow through conduit 40, inlet valve 25a, U-shapedconnector conduit 44, outlet valve 25b and conduit 41 for entry into thefuel well 19 of the engine. Simultaneously with the utilization of thefullrange gasoline, the interior of the cannister assembly isdepressurized by the change in operating state of exhaust start valve25b. With reference to FIGS. 1 and 6, the interior of the cannisterassembly is placed in fluid contact with the carburetor via outletconduit 34, outlet valve 25a and T-shaped conduits 45, having a stem 45awhich connects to the inlet of the carburetor 13. In similar fashion thevapor zones within the fuel well 19 and gas tank 23 are placed in fluidcontact with the carburetor 13 since evaporative control valve 250remains in an inoperative state as depicted in FIG. 1: (i) for fuel well19 via conduit 45, valve 250 and T-shaped conduit 45; '(ii) for gas tank23, via conduit 43, valve 25c and the T-shaped conduit 48. In that way,as desorption of the heavier compounds within the cannister assembly canoccur, say as warmed air or gases are conveyed in heat transfer contactwith the adsorbent bed. These compounds are thereafter swept into thecarburetor 13, along with any evaporative emissions from the fuel well19 and gas tank 24. It should also be pointed out that if evaporativevapors had been previously captured within the adsorptive bed of thecannister assembly, they would likewise be purged at this time.

Modification of the purging operation: in FIG. 4, the conveyance of thehot exhaust gases from the exhaust manifold is under control ofadditional electrical circuitry (not shown) of the controller circuit26. When the temperature of the exhaust manifold reaches a selectedtemperature, a relay (not shown) is tripped to pass the purging gasesthrough the cannister assembly 27 of FIGS. 4 and 5 via conduit 61. Thedesorbed materials within the adsorption bed of the cannister assembly27 are ultimately consumed within the combustion chambers of the engineusing the appropriate valve and conduit positions as previouslydescribed with reference to FIG. 1.

Where the heavier compounds within the adsorption bed of the cannisterassembly have relatively high boiling points, too high in fact to berenewed by passing ad jacent engine air in heat transfer contact withthe elution zone, the embodiment depicted in FIG. 4 is especiallyuseful. In this regard, the adsorbent material 56 of FIG. 4 can berenewed using the hot exhaust gases as the purging agent. If thetemperature of such exhaust gases ranges from 700 to about 800F, only arelatively short desorption time is required. Temperature of theadsorbent bed can be a range from 400-500F with about 450F being asatisfactory operating temperature. Generally desorption time is quiteshort for such range setting, say being from about 2-l2 minutes induration. The resulting desorbed compounds then pass through the airintake system and carburetor 13 to the combustion chambers where theyare consumed. Even though the cannister assembly 27 of FIG. 4 is largerthan that depicted in FIG. 2, it provides better heattransfercharacteristics during desorption of the adsorption bed since theavailable heat transfer area (between the heat transferring media) ismuch larger. That is to say, the shell-side hot gases traveling throughthe cannister assembly 27 of FIG. 4 is in extremely good heat transfercontact with a multiplicity of the tubular member means. Also, sincetemperature of the gases is much higher, the total purge time can bereduced. However, the total flow rate of the hot purged gases at the airintake system should be carefully controlled so that the compositetemperature of the inlet air to the carburetor is not too hot forefficient utilization of the resulting air fuel mixture within thecombustion chamber of the engine.

FIG. 7 illustrates yet another mode for desorbing the adsorption bed ofthe cannister assembly of the present invention. In accordance with theillustrated embodiment, engine air is heated by passing the air adjacentto exhaust manifold 70 and thence through the cannister assembly wheredesorption occurs. The exhaust manifold 70 itself is provided with anexterior hood 71 having lower skirts 72 which snuggly fit adjacent tothe exhaust manifold, yet are open to incoming air. A central register73 is also provided with a nozzle 74. Nozzle 74 in turn is attached byflexible conduit 75 connected at a port 76 say at the air intake line16a of the air intake system. At the air intake line 16a, a solenoidoperator 77 is positioned so that damper 78 is in register with port 76.Opening the damper 78 allows warmed engine air to enter the cannisterassembly (not shown).

Sequence of Operations Reference should not be had to FIGS. 1, 2, 4-6,and 8 illustrating the method aspects of the present invention. In moredetail, it should be apparent that the initiation of the cold startcycle automatically occurs when the driver closes ignition switch 260 ofthe controller circuit 26 of FIGS. 1 and 4. Before the driver engagesthe ignition switch 26c, however, the valve and conduit network 25 andparticularly the evaporative control valve 25c is in the positionillustrated in FIG. 8 to carry out the vapor adsorption control functionof the present invention. That is to say, the evaporative 3-way controlvalve 250 is in a relaxed state so that the conduits 35, 42 and 43 arein fluid communication so that the interior of the cannister assembly isconnected with the vapor zones of the carburetor and the gas tank. Whenthe engine is in an inactive state and evaporation of the fuel occurs,the vapors then are free to pass through these conduits to theadsorption bed of the cannister assembly of FIGS. 2 and 4. Adsorption ofthe vaporprevents its escape into the atmosphere.

Prior to initiation of cold start, assume the fuel well 19 has beenemptied of full-range fuel. In this regard, consider also the functionof drain conduit 47 of FIGS. 1 and 4 connected between fuel well 19 andgas tank 23. When the engine is in an inactive state, fuel within thefuel well 19 (liquid phase) drains therefrom via conduit 47 to the gastank 23. As shown, the conduit 47 is provided with an oriface 48 so asto control the rate of drainage of the fuel, say at a rate which willallow total removal of all fuel from the well within. a 6l2 hour period.Thus, when the engine is parked overnight, the drain conduit 47 incooperation with orifice 48 provide for total removal of full-range fuelfrom the fuel well 19. It should also be apparent that if the drainageconduit 47 is mounted at the sidewall of the fuel well (not at thebottom wall as shown) not all of the full-range fuel will be drained.Instead, a residual reservoir remains, the amount of which is a functionof the connector position relative to the top wall of the fuel well,e.g., if the connector to the fuel well and conduit is at a location sayabout two-thirds of the way away from the top wall, the residual fuelwould be one-third of the total fuel well capacity. During initialstarting of the engine, the position of nozzle 20 of the carburetor 13could be arranged, depthwise, so that a selected, compatible mixture ofthe residual and eluted fuel would enter the carburetor to effect coldstart of the engine.

As the engine turns over, the fuel pump 24 conveys full-range fuelthrough inlet start valve 25a to the cannister assembly 27 of FIGS. 2 or4. Within the cannister assembly 27, the full-range fuel percolatesthrough the adsorption bed culminating in the elution of paraffiniccomponents at fuel well 19. From the fuel well 19, a metered amount ofthe paraffinic components is conveyed via nozzle 20 into the carburetor13 where the fuel and air are properly mixed and then convey forconsumption within the combustion chambers of the engine. After selectedrise in the engine temperature, as measured by bimetal switch 26b of thecontroller circuit 26, say positioned at the water jacket or exhaustmanifold of the engine, control relay 26a becomes deactivated, resultingin the cold start inlet and exhaust valves 25a and 25b returning torelaxed positions as shown in FIG. 6.

After the cold start exhaust and inlet valves 25a and 25b return torelaxed positions depicted in FIG. 6, the fuel intake system switchesover to full utilization of the full-range gasoline. That is to say,fuel conveyed from fuel pump 24 passes via conduit 40 to inlet valve 25aand thence through U-shaped conduit 44, exhaust cold start valve 25b andconduit 41 to the fuel well 19. As full-range fuel is used, theadsorption bed of the cannister assembly is depressurized by itsplacement in fluid contact with the carburetor inlet.

It should be pointed out that during the operation of the engine, theevaporative control valve 250 of the valve and conduit network 25remains in an activated state as depicted in FIGS. 1, 4 and 6. However,when the driver opens the ignition switch 26c of the controller circuit26, the evaporative control valve 25c is activated through relaxation ofrelay 266 which places it in the position depicted in FIG. 8 whereby theadsorption bed of the cannister assembly 27 is then in direct vaporcontact with the fuel well 19 and gasoline tank 23. In that way, asevaporative emissions are formed within the fuel well 19 or the gasolinetank 23, they are conveyed to the interior of the cannister assembly.

While the certain preferred embodiments of the invention have beenspecifically disclosed above, it should be understood that the inventionis not limited thereto as many variations will be readily apparent tothose skilled in the art and thus the invention is to be given thebroadest possible interpretation within the terms of the followingclaims.

I claim:

1. In a spark-ignition internal combustion engine of the type having anair intake system, a fuel system, and a mixing means interconnectedtherebetween for mixing of full-rangefuel with air to form a combustiblemixture for delivery to combustion chambers of said engine, theimprovement for reducing exhaust pollutants of said engine by (i)dynamically varying the com- 13 position of said full-range fuel duringcold starting of said engine (cold start cycle) and (ii) alternativelyadsorbing evaporative emissions originating from vapor zones within saidfuel system at least during an inoperative state of said engine,comprising:

i. cannister-means selectively connectable between said mixing means anda reservoir of said full range fuel and including an adsorption bed ofadsorbent material,

ii. control means for controlling fluid flow including liquid fuel aswell as vapor emission flow between said reservoir means, said cannistermeans and said mixing means as a function of selected operatingparameters,

iii. said control means including at least first and second conditionmeans for alternatively (i) initiating, during said cold start cycle,flow of said full-range fuel from said reservoir to said cannister meansand hence over said adsorption bed so as to elute a cold start fueleffluent composed essentially of low molecular weight liquidconstituents, said effluent being passed to said mixing means insufficient amounts to assure starting of said engine, and (ii)permitting flow of evaporation vapors from said vapor zones of said fuelsystem to said same adsorption bed for capture thereon, at least duringsaid inoperative state of said engine.

2. The improvement of claim 1 in which said first condition means isfurther characterized by first and second valve means operative aftersaid engine has started and warmed, to place said reservoir of fuelrangefuel in direct liquid flow contact with said mixing means, at least oneof said valve means being operative to cause depressurization of saidcannister means so as to allow purging of adsorbents within saidadsorbent bed of adsorbent material for ultimate consumption within saidengine.

3. The improvement of claim 1 in which said adsorbent material isselected so as to provide dual functions of: (i) efficient retardationof high molecular weight constituents of said full-range fuelpercolating therethrough whereby essentially only low molecular weightconstituents are eluted from said cannister means during cold startingof said engine, and (ii) effective capture of evaporative emissionsoriginating from said vapor zones of said fuel system during saidinoperative state of said engine.

4. Apparatus for reducing exhaust and inoperative pollutants produced bya spark-ignition internal combustion engine of the type including an airintake system, a fuel intake system, and a mixing means interconnectedtherebetween for mixing fuel with air to form a combustible mixture fordelivery to combustion chambers of said engine, comprising:

i. a cannister assembly containing an adsorbent bed of adsorbentmaterial (a) capable of selectively adsorbing high molecular weightconstituents of a full-range fuel at cold start while elutingsubstantially unimpeded a cold start fuel effluent composed essentiallyof only low molecular weight constituents as well as (b) capable ofselectively absorbing vapor constituents of said full-range fuel duringat least an inoperative state of said engine,

ii. valve and conduit network means attached between said cannisterassembly a reservoir means of said fuel, and said mixing means forproviding selective flow of said cold start fuel effluent between saidcannister assembly, said reservoir means and said mixing means, saidnetwork means including a plurality of conduit and valve means includinga multiplicity of valve means controlling flow relative to saidcannister assembly so as to allow, (a) in a first operating state, flowof said full-range fuel from said reservoir means over said adsorbentbed so as to elute said cold start fuel effluent therefrom, and to passsaid effluent thereafter to said mixing means to provide for rapidstarting of said engine without producing excessive exhaust pollutantsand, (b) in a second operating state, flow of fullrange fuel directlyfrom said reservoir means to said mixing means bypassing said adsorbentbed after said engine is in a normal running condition whilesimultaneously allowing for depressurization of said adsorbent bed,

iii. said plurality of conduit and valve means also including a separatevalve means operatively connected between said adsorbent bed and vaporzones of said fuel reservoir means and said mixing means for selectivelyconveying vapor evaporative emissions originating therein to said sameadsorbent bed when said engine is in said inoperative state,

iv. control means operatively connected to said valve means of saidvalve and conduit network for changing operation states so as to directfuel flow relative to said adsorbent bed, said reservoir and mixingmeans as a function of one or more engine operating parameters.

5. Apparatus of claim 4 in which said cannister assembly includes anenlarged cylindrical shell housing terminating in first and second endpole pieces and including a plurality of radically extending couplingsextending through said housing, said plurality of couplings beingconnected to said reservoir means, said mixing means, and said adsorbentbed, through said valve means, whereby (i) in a first state, to allowthe selective delivery of fuel to said fuel well of said mixing means asa function of a selected engine parameter, and (ii) in a second state,to allow selective vapor contact therebetween whereby evaporativeemissions from said reservoir means and said mixing means can beadsorbed within said same adsorbent bed and thereby not escape into saidsurrounding atmosphere.

6. Apparatus of claim 4 in which said cannister as sembly includes amultiplicity of tubular conduits each arranged parallel to each otherwithin a single tubular shell housing, each conduit supporting a segmentof said bed of adsorbent material but all terminating at central inletand outlet chambers in operative contact with said valve means so as toprovide said dual functions of: (i) cold start elution of low molecularweight cold start constituents and (ii) capture of evaporative emissionsoriginating from said fuel system along sinusoidal paths within saidsingle enlarged housing.

7. Apparatus of claim 6 in which said pole pieces are perforated, onethereof being connected by air intake control means including conduitmeans to a source of heated gas, so as to allow selective flow of saidheated gas through said cannister assembly for purging said adsorbentbed with adsorbed cold start constituents, and evaporative emissions,said purged constituents from said adsorbent bed being carried into andconsumed within said combustion chambers of said engine during normalrunning operation thereof.

8. Process for reducing formation of exhaust pollutants during a coldstart cycle of a spark-ignition internal combustion engine the typehaving an air intake system, a fuel system, including a reservoir meanscontaining a full-range fuel and a mixing means interposed therebetweenwithout affecting full-range engine performance of said engine aftercold starting has been concluded, while simultaneously providing foreffective capture of evaporative emissions originating from vapor zonesof said fuel system at least during an inoperative state of said engine,comprising the steps of:

i. during said cold start cycle, dynamically eluting from saidfull-range fuel passing through an adsorbent bed of adsorbent material,a cold start fuel effluent composed essentially of low molecular weightconstituents,

ii. mixing said low molecular weight effluent with air to form anenriched fuel air mixture for delivery to combustion chambers of saidengine during said cold start cycle where consumption without undueformation of exhaust pollutants occurs,

iii. terminating elution of said cold start fuel effluent after saidengine has started,

iv. switching flow of said full-range fuel directly to saidmixing meansby bypassing liquid fuel flow with respect to said adsorbent bed,

v. purging with heated fluid said adsorbent bed of adsorbates,

vi. conveying said purged constituents into said combustion chambers ofsaid engine, and

vii. after said engine has been placed in an inoperative state, openingvapor conduit means between said same adsorbent bed, said mixing meansand said reservoir means whereby vapor emissions originating from withinsaid fuel system are captured within said same adsorbent bed and herebyprevented from escaping into the atmosphere surrounding said engine.

1. In a spark-ignition internal combustion engine of the type having anair intake system, a fuel system, and a mixing means interconnectedtherebetween for mixing of full-range fuel with air to form acombustible mixture for delivery to combustion chambers of said engine,the improvement for reducing exhaust pollutants of said engine by (i)dynamically varying the composition of said full-range fuel during coldstarting of said engine (cold start cycle) and (ii) alternativelyadsorbing evaporative emissions originating from vapor zones within saidfuel system at least during an inoperative state of said engine,comprising: i. cannister means selectively connectable between saidmixing means and a reservoir of said full-range fuel and including anadsorption bed of adsorbent material, ii. control means for controllingfluid flow including liquid fuel as well as vapor emission flow betweensaid reservoir means, said cannister means and said mixing means as afunction of selected operating parameters, iii. said control meansincluding at least first and second condition means for alternatively(i) initiating, during said cold start cycle, flow of said full-rangefuel from said reservoir to said cannister means and hence over saidadsorption bed so as to elute a cold start fuel effluent composedessentially of low molecular weight liquid constituents, said effluentbeing passed to said mixing means in sufficient amounts to assurestarting of said engine, and (ii) permitting flow of evaporation vaporsfrom said vapor zones of said fuel system to said same adsorption bedfor capture thereon, at least during said inoperative state of saidengine.
 2. The improvement of claim 1 in which said first conditionmeans is further characterized by first and second valve means operativeafter said engine has started and warmed, to place said reservoir offuel-range fuel in direct liquid flow contact with said mixing means, atleast one of said valve means being operative to cause depressurizationof said cannister means so as to allow purging of adsorbents within saidadsorbent bed of adsorbent material for ultimate consumption within saidengine.
 3. The improvement of claim 1 in which said adsorbent materialis selected so as to provide dual functions of: (i) efficientretardation of high molecular weight constituents of said full-rangefuel percolating therethrough whereby essentially only low molecularweight constituents are eluted from said cannister means during coldstarting of said engine, and (ii) effective capture of evaporativeemissions originating from said vapor zones of said fuel system duringsaid inoperative state of said engine.
 4. Apparatus for reducing exhaustand inoperative pollutants produced by a spark-ignition internalcombustion engine of the type including an air intake system, a fuelintake system, and a mixing means interconnected therebetween for mixingfuel with air to form a combustible mixture for delivery to combustionchambers of said engine, comprising: i. a cannister assembly containingan adsorbent bed of adsorbent material (a) capable of selectivelyadsorbing high molecular weight constituents of a full-range fuel atcold start while eluting substantially unimpeded a cold start fueleffluent composed essentially of only low molecular weight constituentsas well as (b) capable of selectively absorbing vapor constituents ofsaid full-range fuel during at least an inoperative state of saidengine, ii. valve and conduit network means attached between saidcannister assembly a reservoir means of said fuel, and said mixing meansfor providing selective flow of said cold start fuel effluent betweensaid cannister assembly, said reservoir means and said mixing means,said network means including a plurality of conduit and valve meansincluding a multiplicity of valve means controlling flow relative tosaid cannister assembly so as to allow, (a) in a first operating state,flow of said full-range fuel from said reservoir means over saidadsorbent bed so as to elute said cold start fuel effluent therefrom,and to pass said effluent thereafter to said mixing means to provide forrapid starting of said engine without producing excessive exhaustpollutants and, (b) in a second operating state, flow of full-range fueldirectly from said reservoir means to said mixing means bypassing saidadsorbent bed after said engine is in a normal running condition whilesimultaneously allowing for depressurization of said adsorbent bed, iii.said plurality of conduit and valve means also including a separatevalve means operatively connected between said adsorbent bed and vaporzones of said fuel reservoir means and said mixing means for selectivelyconveying vapor evaporative emissions originating therein to said sameadsorbent bed when said engine is in said inoperative state, iv. controlmeans operatively connected to said valve means of said valve andconduit network for changing operation states so as to direct fuel flowrelative to said adsorbent bed, said reservoir and mixing means as afunction of one or more engine operating parameters.
 5. Apparatus ofclaim 4 in which said cannister assembly includes an enlargedcylindrical shell housing terminating in first and second end polepieces and including a plurality of radically extending couplingsextending through said housing, said plurality of couplings beingconnected to said reservoir means, said mixing means, and said adsorbentbed, through said valve means, whereby (i) in a first state, to allowthe selective delivery of fuel to said fuel well of said mixing means asa function of a selected engine parameter, and (ii) in a second state,to allow selective vapor contact therebetween whereby evaporativeemissions from said reservoir means and said mixing means can beadsorbed within said same adsorbent bed and thereby not escape into saidsurrounding atmosphere.
 6. Apparatus Of claim 4 in which said cannisterassembly includes a multiplicity of tubular conduits each arrangedparallel to each other within a single tubular shell housing, eachconduit supporting a segment of said bed of adsorbent material but allterminating at central inlet and outlet chambers in operative contactwith said valve means so as to provide said dual functions of: (i) coldstart elution of low molecular weight cold start constituents and (ii)capture of evaporative emissions originating from said fuel system alongsinusoidal paths within said single enlarged housing.
 7. Apparatus ofclaim 6 in which said pole pieces are perforated, one thereof beingconnected by air intake control means including conduit means to asource of heated gas, so as to allow selective flow of said heated gasthrough said cannister assembly for purging said adsorbent bed withadsorbed cold start constituents, and evaporative emissions, said purgedconstituents from said adsorbent bed being carried into and consumedwithin said combustion chambers of said engine during normal runningoperation thereof.
 8. Process for reducing formation of exhaustpollutants during a cold start cycle of a spark-ignition internalcombustion engine the type having an air intake system, a fuel system,including a reservoir means containing a full-range fuel and a mixingmeans interposed therebetween without affecting full-range engineperformance of said engine after cold starting has been concluded, whilesimultaneously providing for effective capture of evaporative emissionsoriginating from vapor zones of said fuel system at least during aninoperative state of said engine, comprising the steps of: i. duringsaid cold start cycle, dynamically eluting from said full-range fuelpassing through an adsorbent bed of adsorbent material, a cold startfuel effluent composed essentially of low molecular weight constituents,ii. mixing said low molecular weight effluent with air to form anenriched fuel air mixture for delivery to combustion chambers of saidengine during said cold start cycle where consumption without undueformation of exhaust pollutants occurs, iii. terminating elution of saidcold start fuel effluent after said engine has started, iv. switchingflow of said full-range fuel directly to said mixing means by bypassingliquid fuel flow with respect to said adsorbent bed, v. purging withheated fluid said adsorbent bed of adsorbates, vi. conveying said purgedconstituents into said combustion chambers of said engine, and vii.after said engine has been placed in an inoperative state, opening vaporconduit means between said same adsorbent bed, said mixing means andsaid reservoir means whereby vapor emissions originating from withinsaid fuel system are captured within said same adsorbent bed and herebyprevented from escaping into the atmosphere surrounding said engine.